Self-contained solar heater and storage device

ABSTRACT

A solar water-heating apparatus comprises an outer container sized and configured to receive a smaller inner container. The inner container includes a pair of openings, one formed in the floor thereof and one formed in the side wall thereof. The side wall and floor of the inner container define a reservoir capable of receiving a liquid. A gap is located between the floors and side walls of the two containers. Once the device has been filled with a liquid, the liquid present within the gap may be heated by solar energy, thereby increasing the temperature thereof. The liquid with the increased temperature becomes less dense and rises relative to the cooler liquid and travels upwards in the gap until the warmer liquid reaches an opening within the side wall of the inner container. The liquid then travels through the opening and back into the reservoir. The re-entry of this liquid through the opening forces cooler liquid out of an opening in the bottom of the smaller container and into the gap, whereby this cooler liquid may be heated by solar energy. This process will continue until the liquid within the container reaches a certain ambient temperature.

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of solar heaters. In particular, the invention relates to a solar heater capable of heating and storing a liquid.

DESCRIPTION OF PRIOR ART

U.S. Pat. No. 2,388,940 discloses a Solar Heater. The disclosed solar heater is designed primarily to utilize the heat rays from the sun for assistance in home heating after sundown or during parts of the day when the sun is not shining. The invention provides for a self-contained solar heater comprising a tank adapted to contain water or other liquids. The tank includes a heating chamber and a storage chamber in open communication with each other. In the disclosed invention, the water heated in the heater chamber is utilized to circulate the water through both the heater chamber and the storage chamber. Sunlight subjected to the heating chamber warms the water contained therein. Once the water has been warmed by the sun, the tank radiates heat for a predetermined period. The solar heater may also be configured to function as a domestic hot water heater.

U.S. Pat. No. 4,419,983 discloses a Device for Passive Solar Heating and Storage of a Liquid. The disclosed invention includes a passive stationary collector. The collector comprises a cylinder with a substantially circular cross-section set in a fixed position, with its longitudinal axis orientated essentially in a vertical north/south plane and at appropriate angle to a local horizontal plane of the earth. The invention includes a plurality of liquid carrying heat absorbing conduits laying lengthwise on the external surface of the cylinder. The conduits convey heated liquid to the upper part of the reservoir internal the to cylinder. In addition, the conduits obtain cooler water from the lower part of the reservoir. The invention further includes a liquid density trap positioned between the reservoir and the conduits. The liquid density trap prevents cooling of the reservoir contents during periods of low radiation by the sun.

U.S. Pat. No. 4,452,231 discloses Integral Solar Water Heaters. The disclosed water-heating apparatus comprises a plurality of longitudinal tubular storage tanks. Adjacent tanks are aligned in the same direction and in the same plane. An aperture located at the bottom of each tank receives a cold water inlet pipe, and an aperture in the upper portion of the tank receives a hot water outlet pipe. Each tank in the array includes a heat conducting plate, and each plate includes a pipe connected thereto. The pipe for each tank is connected to the tank at two points by two openings. The first end of the pipe is connected to the tank near the bottom, while the second end of the pipe is connected to the tank near the top. The second opening near the top of the tank is covered by a counterbalanced valve member. The counterbalanced valve member is pivotally mounted to the tank and is constructed to block the second opening for flow pressures below a given pressure. Accordingly, as cold water is directed into the heater through the cold water inlet pipe, the cold water enters the pipe associated with the plate. Solar energy heats the water in the pipe, creating density changes and causing the water to rise through the pipe towards the top opening. When a particular pressure is reached due to the density change, the valve pivots and thus causes the heated water to flow back into the tank. In this manner, water will continue to circulate until the entire temperature of the storage tank reaches an ambient value. The presence of the valve prevents the water from cooling during the night.

U.S. Pat. No. 5,462,047 discloses a Solar Water-Heater With Integrated Storage. The disclosed hot water heater is configured to be filled isothermally with water at any temperature. Once the tank is full, the tank begins a thermo-siphoning mode. A collector and a storage tank are housed in a unit. The invention combines two principles of solar hot water heating into one. Primarily, cold water is raised to the desired final temperature in one pass through the absorber, thereby achieving good collector efficiencies and a quick response. In addition, once the storage is full, thermo-siphoning circulation sets in automatically and further heats the storage content and/or compensates for heat losses.

SUMMARY OF THE INVENTION

An embodiment of the present invention includes a solar heater for heating a liquid comprising a first container having an upright wall and a second container located within the first container and including an upright wall. The solar heater includes a gap intermediate the walls of the containers. The gap extends around the second container and encompasses the upright wall of the second container.

In an embodiment of the invention, the second container includes a floor connected to the wall of the second container. The wall of the second container includes an aperture, and the floor of the second container includes an aperture. In addition, the first container includes a floor connected to the wall of the first container and an aperture removed from the floor. In an embodiment of the invention, the solar heater includes an upright wall defining the aperture in the first container. The solar heater may also include a cap for mating with the upright wall in order to seal the aperture of the first container. The cap may include threads capable of mating with threads in the upright wall encompassing the aperture of the first container.

In an embodiment of the invention, the second container includes a reservoir for holding the liquid. The reservoir is connected to the gap by an aperture. The invention may also include a valve capable of sealing the aperture in the wall of the second container. The valve prevents the flow of liquid through the aperture when the valve seals the aperture. In and embodiment of the invention, an adhesive attaches the valve to the wall of the second container.

In an embodiment of the invention, the solar heater includes a plurality of ribs. The ribs reside within the gap. In addition, in an embodiment of the invention, the first container and the second container each have a conical cross section.

In an embodiment of the invention, the solar heater includes a heat exchanger disposed within the reservoir. In addition, the solar heater may include reflectors configured to direct sunlight toward the gap. The reflectors may be arranged on a mat.

In an embodiment of the invention, the solar heater includes a spigot assembly interconnected with the reservoir. The spigot assembly configured to drain liquid from the reservoir. The spigot assembly may include a tube and a float. In addition, the spigot assembly may further include a second tube and a valve.

In an embodiment of the invention, the solar heater includes a valve assembly configured to allow the flow of liquid into the reservoir. The valve assembly may include a valve, a float, and a connector connecting the float to the valve. The float is capable of floating on the top of the liquid and causing additional liquid to flow into the reservoir when the liquid level reaches a predetermined level.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a perspective view of an embodiment of the present invention.

FIG. 2 depicts an section view of the invention depicted in FIG. 1.

FIGS. 3A and 3B depict an embodiment of a valve that may be used in an embodiment of the invention.

FIG. 4 depicts a perspective view of an embodiment of the present invention with a portion of a wall removed for illustrative purposes.

FIG. 5A depicts a section view of an embodiment of the present invention.

FIG. 5B depicts a section view of an alternative of the embodiment of the present invention depicted in FIG. 5A.

FIG. 6 depicts a perspective view of an embodiment of the present invention with a portion of the components illustrated in phantom for illustrative purposes.

FIG. 7 depicts a section view of an embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

FIG. 1 depicts a perspective view of an embodiment of the present invention. In FIG. 1, numeral 10 generally indicates a self-contained solar heater and storage device. In the present embodiment, device 10 includes a body portion, generally indicated by numeral 12, a mating cap 14, transparent cover 16 and reflector mat 18.

FIG. 2 depicts a section view of device 10 taken along section line 2 of FIG. 1. Body portion 12 includes a first container 20 and a second container 22. In the embodiment depicted, body portion 12 further includes insulation 24.

In the embodiment depicted, first container 20 includes a side wall 30 and a floor 32. In the present embodiment, side wall 30 has a conical cross-section. Floor 32 mates with side wall 30 along the lower edge of side wall 30 in such a manner as ensuring a liquid tight seal. In the present embodiment, first container 20 further includes an opening 34 opposite floor 32. In the embodiment depicted, a raised portion 36 defines opening 34. Raised portion 36 includes threads, generally indicated by numeral 38.

In the present embodiment, side wall 30 is manufactured from a material capable of absorbing solar energy, such as metal or plastic, for example, polyethylene plastic. In embodiments of the invention, it is preferable that this material have maximum solar absorption capability and thus, side wall 30 may allow for the use of a wall 30 with a thinner cross section than would be utilized in an application in which the outer wall provides insulation. The outer surface of side wall 30 is colored black in order to achieve maximum solar energy absorption. In addition, in embodiments of the invention, the inner surfaces of walls 30 and floor 32 are substantially smooth.

Second container 22 includes side wall 40 and floor 42. In the present embodiment, the connection between side wall 40 and floor 42 is liquid tight and prevents liquid from flowing therebetween. In addition, side wall 40 has a conical-shaped cross-section, as depicted in FIG. 2. It should be noted that if desired first container 20 and second container 22 may have cross-sections other than conical. For example, first container 20 and second container 22 may have hemispherical shapes.

The combination of side wall 40 and floor 42 defines an inner area or reservoir, generally indicated by numeral 44. As shown in FIG. 2, side wall 40 and floor 42 may include or be manufactured from an insulative material having a relatively thicker cross-section, such as plastic. For example, the inventor anticipates that second container 22 may be manufactured from polystyrene or polyurethane.

Referring still to FIG. 2, side wall 40 includes an opening 46. In the present embodiment, opening 46 is located in side wall 40 at an end opposite where side wall 40 joins with floor 42. In addition, floor 42 also includes an opening 48. Opening 48 may be positioned anywhere within floor 42.

Referring still to FIG. 2, first container 20 is sized and configured to receive second container 22. Accordingly, the outer surfaces of side wall 40 and floor 42 are separated from the inner surfaces of side wall 30 and floor 32. Numeral 60 generally indicates the gap defined by the separation. It should be noted that opening 46 and opening 48 both extend from reservoir 44 into gap 60. In addition, it should further be noted that gap 60 is substantially constant in size around the circumference of side wall 40.

Referring still to FIG. 2, cap 14 includes a plurality of threads 62. In the present embodiment, threads 62 are configured to mate with threads 38. Accordingly, cap 14 may be threaded onto first container 20, thereby sealing off access to reservoir 44. When a user desires access to reservoir 44, however, the combination of threads 38 and 62 allows a user to remove cap 14 from body portion 12. In the present embodiment, cap 14 is manufactured from an insulative material in order to minimize any heat loss from the device 10.

Operation of the device 10 will now be described. Device 10 functions by absorbing solar energy and heating any liquid stored therein. In the present example, water will be used for exemplary purposes. However, it should be noted that device 10 is not limited to the heating of water, but rather will succeed in heating any liquid. The first step in the usage of device 10 requires the removal of cap 14 from body portion 12. This may be accomplished in the present embodiment by rotation of cap 14 in order to disengage threads 62 from threads 38. Once cap 14 has been removed from body portion 12, the liquid to be heated by the device 10 is added to reservoir 44. As should be understood by one skilled in the art, the opening 48 in floor 42 allowing flow from reservoir 44 into gap 60 will ensure that the level of liquid in gap 60 is substantially equivalent to the level of liquid in reservoir 44. A sufficient amount of liquid should be added to device 10 in order to ensure that the liquid level rises above the level of opening 46 in side wall 40.

After the device has been filled with a sufficient volume of liquid, cap 14 may be reattached to body portion 12. Device 10 may then be set out in the sunlight in order to absorb solar energy. It should be noted that in the present embodiment of the invention, the conical arrangement of side walls 30 and 40 ensures that more solar radiation is absorbed by device 10 from the sun than that which would be absorbed if device 10 had a cylindrical orientation. This occurs because the conical shape presents a greater surface area to the sun than that which would be achieved if a cylindrical shape were used.

The solar energy transmitted from the sun to device 10 may be absorbed by a portion of side wall 30 and transferred to the water contained within gap 60. This transfer of solar energy results in the increase in the temperature of the water. As the water temperature increases, the density of the water decreases. Accordingly, water with an increased temperature will begin to flow upward in the direction of arrow 64A.

The warm water continues warming within device 10 and continues to migrate within gap 60 until the water reaches opening 46. Once the water reaches opening 46, the water travels through opening 46 into reservoir 44 as indicated by arrow 64B. The water entering reservoir 44 along the line of arrow 64B is warmer than the water already present within reservoir 44. Accordingly, the warmer water will remain in the upper portion of reservoir 44. In order to accommodate the arrival of this warmer water, cooler water near the bottom of reservoir 44 is forced out of reservoir 44 through opening 48 as indicated by arrow 64C.

This cooler water travels through the portion of gap 60 intermediate floor 32 and floor 42 until the water reaches the area of gap 60 intermediate side wall 30 and side wall 40. At this point, the sun again heats the water, thereby causing the liquid to migrate as indicated by arrow 64A. This process repeats itself until a steady state temperature has been reached. It should be noted that this process will succeed in heating a liquid which has a higher density at cooler temperatures, such as water. Theoretically, during the heating of a liquid that achieves a greater density at higher temperatures, the opposite would happen. Specifically, cooler liquid would exit reservoir 44 through opening 46, travel downward through the portion of gap 60 intermediate side wall 30 and side wall 40, and return into reservoir 44 at a warmer temperature through opening 48. It should be noted in embodiments of the invention a transparent cover 16 may encompass the device 10 in order to entrap heat. In addition, the inventor also foresees the use of reflectors to increase the amount of sunlight directed upon body portion 12. For example, body portion 12 may sit upon a reflector mat 18 capable of reflecting sunlight onto side wall 30. Reflector mat 18 represents a mat manufactured of reflective material capable of redirecting sunlight toward body portion 12.

When one wishes to remove the warm water contained by the device 10, one need only unscrew mating cap 14. The removal of cap 14 presents one with access to reservoir 44. One may then remove water from the reservoir 44 as one desires. In order to function properly again, additional water must be added to reservoir 44 in order to ensure the level of the water is above opening 46.

FIGS. 3A and 3B depict a check valve 70 which may be employed in embodiments of the invention. Check valve 70 is configured to be used in conjunction with opening 46 when water or a similar liquid is being heated. In the embodiment shown, check valve 70 comprises a plastic body 72 and an adhesive 74. Plastic body 72 is generally manufactured from a plastic material having a density less than that of water, thereby allowing plastic body 72 to float within water. Adhesive 74 must be water insoluble and must have sufficient strength to allow plastic body 72 to be attached to the inner surface of side wall 40 without being pulled away when pressure is applied to the plastic body 72. FIG. 3A shows the functioning of check valve 70 when water is flowing into reservoir 44. During the usage as shown in FIG. 3A, sunlight would be shining on side wall 30, as discussed with respect to FIG. 2. Accordingly, water indicated by arrow 76 is flowing into reservoir 44 through opening 46. The water supplies a pressure sufficient to ensure that plastic body 72 contorts or moves, thereby allowing the water to flow through opening 46.

FIG. 3B depicts the check valve 70 functioning when solar energy is no longer available. In this instance, water is no longer flowing through opening 46 because the water is no longer being heated within gap 60. Accordingly, there is insufficient water pressure to displace the plastic body 72 of the check valve 70, and check valve 70 seals opening 46, thereby preventing water from exiting the reservoir 44. This occurs as the less dense check valve 70 floats in the water, and due to the inward sloped of wall 40 attributed to the conical shape thereof, seals the opening 46. Since the water contained by reservoir 44 is greater insulated against the relatively cooler external air than the water contained within gap 60, a greater amount of heat is retained by water within reservoir 44, vis-à-vis, the water present within gap 60. It should be noted that because the relatively warmer water in the reservoir 44 cannot travel out of opening 46 due to the check valve 70, cool water located within gap 60 cannot flow back into reservoir 44 through opening 48. Thus, the presence of check valve 70 prevents reverse flow of water and generally allows the device 10 to maintain a relatively warm water temperature within reservoir 44. It should be noted that in embodiments of the invention, the inventor anticipates the utilization of other check valves known in the art.

FIG. 4 depicts a perspective view of an additional embodiment of the present invention, generally indicated by numeral 110. In this figure, a portion of side wall 30 has been removed in order to show more easily the outer surface of side wall 40 of device 110. In device 110, side wall 40 includes a plurality of ribs, each indicated by numeral 50. The ribs 50 may be integrally formed within the side wall 40. In alternative embodiments of the invention, the ribs 50 may be added to side wall 40 as a separate component and held thereto by an adhesive. The presence of ribs 50 in device 110 ensures that gap 60 is sized consistently throughout device 110. In order to ensure proper functioning of device 110, however, ribs 50 should not extend as far downward as floor 42. This allows a liquid being heated by the device to flow around the periphery of side wall 40 before being directed into channels 52 defined by ribs 50. In addition, ribs 50 should not extend upward as far as the level of opening 46. Thus, the liquid heated by device 110 will be allowed to intermix above ribs 50 before flowing through opening 46 and back into reservoir 44.

FIG. 5A depicts a section view of an alternative embodiment of the present invention, generally indicated by numeral 210. In device 210, side wall 30 further includes an additional opening 53, and side wall 40 further includes an additional opening 54. A spigot assembly 220 extends into reservoir 44 through openings 53, 54 in order to allow removal of warm water from reservoir 44. Ideally, spigot assembly 220 is utilized once the liquid within reservoir 44 has reached a relatively constant temperature. Spigot assembly 220 includes tube 222 and valve 224 of a type known in the art. When a user desires to drain all or a portion of the liquid within reservoir 44, the user need only turn on the valve 224 of the spigot assembly 220. This will allow liquid from reservoir 44 to flow through tube 222 and exit out of tube 222 at opening 226. It should be noted that in this embodiment of the invention, in order to ensure device 210 functions properly, liquid must be added to reservoir 44 after removal of liquid through spigot assembly 220, thereby ensuring that the water level rises above the level of opening 46.

FIG. 5B depicts a modified version of the embodiment of the invention depicted in FIG. 5A. In FIG. 5B, device 210 further includes a float 230 and tube 232. Float 230 is comprised of a material less dense than the liquid thereby ensuring float 230 floats on the top of the liquid. Tube 232 may be manufactured from a flexible material, such as plastic. In the present embodiment, one end of tube 232 is attached to tube 222 of spigot assembly 220. If necessary, tube 222 may be elongated in order to ensure a sufficient length of tube 222 extends into reservoir 44. The opposing end of tube 232 is affixed to float 230.

The embodiment of the invention depicted in FIG. 5B would be utilized in a situation where one desires to always drain the warmest liquid from reservoir 44. Specifically, float 230 floats on the top of the liquid contained within reservoir 44. As explained above, due to density differences in the liquid at different temperatures, warmer liquid generally migrates to the upper portion of reservoir 44. Accordingly, the combination of float 230 and tube 232 ensures that generally the top layer of liquid is being drained through spigot assembly 220, thereby ensuring that one is draining the warmest liquid from reservoir 44.

FIG. 6 depicts another embodiment of the invention, generally indicated by numeral 310. Device 310 includes a heat exchanger 312. Heat exchanger 312 includes an outlet pipe portion 320, inlet pipe portion 322 and exchanger portion 324. In addition, in the embodiment of device 310 depicted, wall 30 includes openings 326, 328 and wall 40 (FIG. 2) includes similar openings (not shown). In the embodiment depicted, outlet pipe portion 320 extends through opening 326 and the corresponding opening in wall 40. Similarly, inlet pipe portion 322 extends through opening 328 and the corresponding opening in wall 40. Any sealant known in the art may be used to ensure a liquid tight seal occurs between the pipe portions 320, 322 and the openings 326, 328.

In the present embodiment, exchanger portion 324 resides within reservoir 44. Exchanger portion 324 interconnects the pipe portions 320, 322. Exchanger portion 324 may be manufactured from any material allowing for high heat conductivity, such as copper.

In operation, device 310 may be utilized to heat any fluid capable of flowing through heat exchanger 312. For example, the fluid to be heated enters heat exchanger 312 via pipe portion 322. The fluid then enters the exchanger portion 324. It should be noted that since the liquid within reservoir 44 has been heated by solar energy, as described above, the flow of fluid through exchanger portion 324 allows the fluid to absorb heat energy from the liquid within reservoir 44. The heat energy absorbed by the fluid increases the temperature of the fluid. The fluid then exits heat exchanger 312 via pipe portion 320 at a temperature greater than that of the fluid when the fluid entered heat exchanger 312.

FIG. 7 depicts another embodiment of the present invention, generally indicated by numeral 410. Device 410 includes spigot assembly 220, as described above. In this embodiment, spigot assembly 220 is positioned proximate the upper surface of the liquid stored within reservoir 44.

Device 410 includes two additional openings 414, 416 and a float valve assembly 420. Float valve assembly 420 may be of any known type. Wall 30 includes opening 414, and wall 40 includes opening 416.

In the present embodiment of the invention, float valve assembly 420 includes a float 422, connection 424, valve 426, inlet pipe 428 and opening 430. Float 422 is comprised of a material with a density allowing float 422 to float on top of the liquid contained within reservoir 44. Connection 424 comprises any connection known in the art and connects float 422 to valve 426 in a known manner. Connection 424 is such that when the level of liquid within reservoir 44 falls to a given level, as measured by float 422, connection 424 activates valve 426. Activation of valve 426 allows additional liquid to flow through valve 426 from inlet 428. The additional liquid then enters reservoir 44 via opening 430. Liquid will continue to flow into reservoir 44 through opening 430 until the liquid reaches a predetermined level. Once this predetermined level is reached, float 422 interacts with connection 424 to shut off valve 426 thereby stopping the flow of liquid into the reservoir 44.

It should be noted that in the present embodiment, spigot assembly 220 is positioned proximate the upper surface of the liquid within reservoir 44. Conversely, valve 426 and inlet 428 are positioned proximate floor 42. As explained above, generally warmer liquid is located at the top of reservoir 44 and cooler liquid is located near the bottom of reservoir 44. Thus, in the present embodiment, spigot assembly 220 draws off warmer liquid from reservoir 44. Moreover, cooler liquid from inlet 428 intermixes with the cooler liquid contained within reservoir 44. The inclusion of additional cooler liquid in the lower portion of reservoir 44 causes relatively warmer liquid to flow upwards in reservoir 44, based upon the difference in density of liquid at different temperatures. Accordingly, in the present embodiment of the invention, spigot assembly 220 is able to draw out the relatively warmer liquid from reservoir 44.

It should be noted that the inventor also anticipates that one may include the float 230 and tube 232 combination depicted in FIG. 5B, with the spigot assembly 220 of the present embodiment. This combination of components allows for flexibility in height when positioning the spigot assembly within body 12.

While this invention has been described as having an exemplary design, the present invention may be further modified within the spirit and scope of this disclosure. The application is, therefore, intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains. 

1. A solar heater for heating a liquid including: a first container having an upright wall; a second container located within the first container and including an upright wall; and a gap intermediate the wall of the first container and the wall of the second container; wherein the gap extends around the second container and encompasses the upright wall of the second container.
 2. The solar heater for heating a liquid as set forth in claim 1 wherein the second container further includes a floor connected to the wall of the second container.
 3. The solar heater for heating a liquid as set forth in claim 2 wherein the wall of the second container includes an aperture and the floor of the second container includes an aperture.
 4. The solar heater for heating a liquid as set forth in claim 1 wherein the first container includes a floor connected to the wall of the first container and an aperture positioned apart from the floor.
 5. The solar heater for heating a liquid as set forth in claim 4 wherein an upright wall defines the aperture in the first container.
 6. The solar heater for heating a liquid as set forth in claim 5 further including a cap for mating with the upright wall and sealing the aperture.
 7. The solar heater for heating a liquid as set forth in claim 6 wherein the cap includes threads and the upright wall includes threads that mate with the threads of the cap.
 8. The solar heater for heating a liquid as set forth in claim 3 wherein the second container includes a reservoir for holding the liquid, the reservoir connected to the gap by the aperture.
 9. The solar heater for heating a liquid as set forth in claim 8 further including a valve capable of sealing the aperture in the wall of the second container in order to prevent flow of the liquid through the aperture.
 10. The solar heater for heating a liquid as set forth in claim 9 further including an adhesive for attaching the valve to the wall of the second container.
 11. The solar heater for heating a liquid as set forth in claim 1 further including a plurality of ribs intermediate the wall of the first container and the wall of the second container.
 12. The solar heating for heating a liquid as set forth in claim 1 wherein the first container and the second container are each of a conical cross section.
 13. A solar heater for heating a liquid including: a reservoir for storing the liquid; and a gap encompassing the reservoir and connected to the reservoir by an upper aperture and a lower aperture.
 14. The solar heater for heating a liquid as set forth in claim 13 further including a first upright wall and a floor defining the reservoir, the upper aperture being disposed in the first upright wall and the lower aperture being disposed in the floor.
 15. The solar heater for heating a liquid as set forth in claim 13 further including a valve capable of sealing the upper aperture in order to prevent the flow of liquid through the aperture.
 16. The solar heater for heating a liquid as set forth in claim 13 further including a second upright wall positioned adjacent the gap and opposite the first upright wall.
 17. The solar heater for heating a liquid as set forth in claim 13 further including a transparent cover encompassing the gap and the reservoir.
 18. The solar heater for heating a liquid as set forth in claim 13 further including a threaded cap capable of sealing the reservoir.
 19. The solar heater for heating a liquid as set forth in claim 13 further including a heat exchanger disposed within the reservoir.
 20. The solar heater for heating a liquid as set forth in claim 13 further including reflectors configured to direct sunlight toward the gap.
 21. The solar heater for heating a liquid as set forth in claim 20 further including a mat, the reflectors being arranged on the mat.
 22. The solar heater for heating a liquid as set forth in claim 13 further including a spigot assembly interconnected with the reservoir, the spigot assembly configured to drain liquid from the reservoir.
 23. The solar heater for heating a liquid as set forth in claim 22 wherein the spigot assembly includes a tube and a float.
 24. The solar heater for heating a liquid as set forth in claim 23 wherein the spigot assembly further includes a second tube and a valve.
 25. The solar heater for heating a liquid as set forth in claim 13 further including a valve assembly configured to allow the flow of liquid into the reservoir.
 26. The solar heater for heating a liquid as set forth in claim 25 wherein the valve assembly includes a valve, a float, and a connector connecting the float to the valve, the float being capable of floating on the top of the liquid and causing additional liquid to flow into the reservoir when the liquid level reaches a predetermined level. 